The Winter Queen

Elizabeth of Bohemia, nicknamed the Winter Queen, starts an affair with an African prince that can only be consumed in secret.
An exquisite sketch of political intrigues in Europe; about money, trade, power, ideals, and religious and family disputes.

Trivia:

Also published as Astraea.
This story finds its sequel in the novel The Pretender, set in London and on the Isle of Barbados.